Typically a beverage, such as soda pop and beer, is dispensed by automated machinery into individual cans each comprising an open top, which is later capped. See the disclosures of U.S. Pat. Nos. 4,387,748 and 4,750,533.
Such automated machinery comprises fill valves by which pressurized gas and beverage are delivered into each can through the open top thereof. Prior art fill valves comprise an array of beverage influent flow paths and a standard distal beverage effluent nozzle comprising an array of downwardly and outwardly directed beverage passages, often ending in exposed discharge tubes. In the past, with 204 sized cans and larger, this standard effluent nozzle was diametrally sized to fit through the opening in the top of a can of predetermined size on a close tolerance basis so that the discharge streams of beverage are emitted from relatively low locations within the interior of the can and strike against the inside surface of the side wall of the can. The flow distance between the end of each discharged stream and the side wall of the can is minimal so that beverage foaming is kept within tolerable limits.
Particularly in respect to cans made of aluminum, the beverage industry has continually sought ways to reduce the amount of aluminum used to fabricate each can. The thickness of the side wall has been materially reduced. Also, from time to time the beverage industry has reduced the size of the lid placed upon the aluminum can in its quest to further reduce the amount of aluminum used. Reduction in lid size correspondingly reduces the pre-lid top opening in the can.
In recent times, this trend has reduced the can top opening size first from a 206 size to a 204 size and more recently to a 202 size. A further reduction to a size 114 is anticipated. The size designations mentioned above (206, 204, 202, and 114) are codes which identify the diameters of the lids, i.e. 26/16", 24/16", 22/16", and 114/16", respectively. With such reductions in aluminum lid sizes and corresponding reduction in the size of openings at the top of aluminum cans comes obsolescence of certain parts of the beverage-filling machinery. For example, a size #204 can will not accept the distal discharge nozzle structure of the pre-existing standard fill valves when lowered due to dimension interference. Thus, the progressive trend by the beverage industry to smaller and smaller lids and, therefore, smaller and smaller openings at the top of aluminum cans leaves existing fill valves nonaccommodating. The normal solution in the past to this problem has been to replace the entire old dimensionally-nonaccommodating fill valves with smaller fill valves of the same design which fit, on a close tolerance basis, through the smaller top opening of the cans. However, this replacement approach, on both a plant and an industry-wide basis, is very costly especially when considering that heretofore each new lid size typically has required total replacement of all existing fill valves in each plant. To reduce the costs associated with such plant conversions, the nozzle adapters forming the subject matter of U.S. Pat. No. 5,141,035 were created.
Furthermore, other problems are created by use of cans having progressively smaller openings in conjunction with existing fill valves of standard design or modified at the discharge nozzle, which are not addressed by merely miniaturizing or modifying existing fill valve configurations.
Attempted fill valve conversions to include a modified nozzle portion is accompanied by a need to discard many of the older fill valves during the attempted conversion due to excessive corrosion, pitting, worn out counterpressure tubes, troublesome snift tubes, nut and plunger assemblies, and other damage accumulated over years of use. These disadvantages together with the costs of labor, machine work, and materials required to salvage older fill valves and to convert them for use with cans having smaller openings have provided a strong motivation to invent new fill valves, which effectively, efficiently, and cost-effectively accommodate filling of cans comprising smaller openings.
A further impediment to efficient transformation to cans comprising smaller openings has been the old snift systems. It has long been the practice of the industry that the snift release must come from the back side of the valve and can, so as not to pull product out of the can during the snift cycle. Otherwise, it was believed that a wet snift would occur resulting in product loss through the snift release and an unstable product in the can. More specifically, it was believed that the centrifugal force of the filler rotation puts the product in the can on a high angle at the front of the can. Therefore, by locating the snift release at the rear portion of the can and valve, product loss due to a wet snift would be reduced. Accordingly, the complicated machinery and involved methods of rear snifting the CO.sub.2 gas from the can were used. However, with the advent of cans comprised of very small openings, rear snifting sometimes slows the rate at which canned products can be produced with automatic beverage filling machinery and puts into place a higher incidence of product instability.
Many if not most or all fill valve designs feed product in parallel through a plurality of side-by-side tubes into one can. Typically, the number of influent flow paths equals the number of effluent flow paths. Heretofore, the distal ends of fill valve tubes extend downwardly beyond the remainder of the fill valve to a location a substantial distance into the can so as to become submerged in the product within the can in order to precisely facilitate fill valve shut off. This technique creates a discharge region for the product entering the can from one-third to one-half way down the interior of the can wall when cans with larger openings are used, but invariably causes a wild foaming condition resulting in short fills when cans with smaller openings are used. This may also leave air trapped in the finished product.
Whenever a foaming problem is encountered, no matter what the reason, an undesirable reduction in the rate of production is inevitably a consequence and, sometimes, the product must be expensively refrigerated prior to canning.
Certain prior fill valve configurations prevent advantageous revision to the sealing gasket and the manner in which counterpressure CO.sub.2 is delivered to and prevented from leaking across the sealing gasket to the atmosphere when used to fill cans comprising smaller openings, which causes short fill cans, foaming, and can flood the product bowl if the filler is shut down with cans on the machine.
Facile setting of a desirable fill height has also been a problem of trying to adapt older beverage filling equipment to cans having smaller openings.
Further, adaptation in the industry over time to each can successively having a smaller opening has been piecemeal i.e. a series of changes to filling equipment applicable only to cans comprising the next smaller opening, which changes do not work well for later cans comprising even a smaller opening. Permanent machinery solutions for cans of successively smaller openings have not been forthcoming within the industry.
A further problem is presented by automated filling of cans having a smaller opening. Specifically, with the delivery of product from the fill valve at a higher location, the amount of CO.sub.2 gas required in the head space and the snift chamber of the fill valve has increased. This increase in the required CO.sub.2 undesirably slows the rate of production using existing automatic filling machinery.
A related problem involves the requirement that can filling occur through an array of tubes of the fill valve, which distally extend into and are submerged within the product placed in the can to accommodate ball cage shut off of the fill valve. Continued use of such an array of product discharged tubes (sometimes with staggered lengths to compensate for an angle created in the product in the can due to centrifugal force) has increased the rate at which cans with smaller openings are damaged when the can is placed on the fill valve. Also, these tubes undesirably carry away product from the can when removed, resulting in loss of product.
Also, in certain prior installations, a screen for each circular beverage passageway has been used creating certain problems. These individual screens cause both production and maintenance problems. These individual screens typically are from 30-34 mesh and these screens and their related tubes are very bothersome from a maintenance standpoint. During the canning of beer, these screens get a build up on them referred to in the industry as beer stone. Beer stone in time will plug the screen and cause foaming and/or short fills.
Prior can sealing gaskets also do not work well with cans having smaller openings, because of a high incidence of interference and can damage problems.